Refrigeration



Dec. 3, 1935. c. G. MUNTERS REFRIGERATION Original Filed Feb. 9, 1935 INVENTOR.

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Patented Dec. '3, 1935 REFRIGERATION Carl Georg Munters, Stockholm, Sweden, as-

signor, by mesne assignments, to Servel, Inc., Dover, Del., a corporation of Delaware Original application February 9, 1933, Serial No.

Divided and this application July 18,

1934, Serial No. 735,776. In Germany March 1': Claims. (01. 62-118) My invention relates to refrigeration and more particularly to automatic control or regulation of intermittent absorption refrigeration apparatus. This application is a division of my application Serial No. 655,881.

It is an object of my invention to provide automatic control or regulation of flow of fluid in an absorption refrigeration system without the use of valves or other mechanical moving parts.

Another object is to automatically control the operation of a vaporization-condensation element or fluid heat transfer circuit without the use of mechanical moving parts.

A further object is to provide an eflicient arrangement for cooling a generator-absorber of an intermittent refrigeration system only during the absorption periods and which requires no valves or other mechanical moving parts.

The above objects are attained, in accordance with my invention, by controlling circulation of fluid responsive to heat. This I accomplish by elevating or preventing a normally downward flow of liquid responsive to heat by thermosiphon or vapor liquid lift action.

The nature of my invention, together withthe objects and advantages thereof, will be more fully understood upon consideration of the following description and accompanying drawing forming part of this specification and of which:

The figure shows schematically an intermittent absorption refrigeration apparatus embodying my invention.

Referring to the drawing, a generator-absorber Ill comprises an upright cylindrical vessel through which extends a heating flue I I. A gas burner I2, provided with a suitable control valve I3, is arranged so that, when the burner is lighted, the flame projects upwardly into the lower end of the flue II The upper part of the generator I0 is connected by a conduit l4 to'.an air-cooled condenser I5, and the latter is connected by a conduit I6 to an evaporator II. The generator It contains a solution of refrigerant in an absorbent, for instance, a water solution of ammonia. In operation, the generator-absorber I0 is alternately heated, as by the burner I2, and cooled. The alternate heatingand cooling may be accomplished automatically. During the heating periods, ammonia vapor is expelled from solution in the generator-absorber, condensed to liquid in the condenser l5, and accumulated in the evaporator II. During the cooling periods, the ammonia evaporates in the evaporator I1, the vapor flowing through conduit I 6, condenser I5,

and conduit I4 to the generator-absorber I0, where the vapor is absorbed into the solution from which it was previously expelled. It will be understood that. refrigeration systems of this general type are well-known in the art and the 8 system illustrated constitutes no limitation with respect to the present invention which may be embodied in any refrigeration system of the absorption type.

For cooling the generator II], I provide a fluid circuit embodying my invention. Around the generator-absorber I0 is located, in thermal conductive relation therewith, a coiled tube I8, which may be referred to as a cooling coil and is adapted to conduct cooling liquid in thermal exchange relation with the generator-absorber ashereinafter described. The upper end IQ of the cooling coil I8 is connected to one end of a second air-cooled condenserZIl. As illustrated, the con- 'densers I5 and may be arranged adjacent each 20 other and provided with common heat radiation fins 2|. The other end of the condenser 20 is connected to the upper part of a first vessel 22 which may be referred to as a collecting vessel. At a level below that of the collecting vessel 20 is located a second vessel 23. The lower part of the upper vessel 22 is connectedto the lower part of the lower vessel 23 by a conduit 24, the latter having a portion 25 coiled around the conduit I4 in thermal exchange relation therewith. From the upper part of vessel 22 to the upper part of the lower vessel 23 is connected a conduit 26 which may be referred to as either a pressure equalizing or overflow conduit. The upper part of the lower vessel 23 is connected to the lower end of the cooling coil I8 by a conduit 21. The circuit comprising the cooling coil I8, condenser 20, vessels 22 and.,23, and the interconnecting conduits is partially filled with a suitable volatile cooling liquid, preferably one having a low vapor pressure at the normal room temperature, such as benzol, pentane, or the like. The tubes forming conduit 24 and the cooling coil I8 are preferably of sufficiently small cross-sectional area that liquid and vapor cannot pass each other therein, whereby these t'ubes constitute narrow thermosiphon or gas lift elements in which upward flowof liquid therein upon the application of heat is made more positive by the pump efiect created by rising vapor trapped in the liquid.

In operation, assuming that heating of the generator-absorber has been discontinued to instigate a refrigerating or cooling period, liquid which is now permitted, as hereinafter described, I

to enter the coil l8, vaporizes, the heat of vaporization being supplied by transfer from the generator-absorber to cool the latter. The formation of vapor in the coil l8 creates an upward flow of liquid therein in a manner well-known in the art. As a result, both vapor and liquid are delivered from the upper end I 9 of the cooling coil 18 to the condenser 20. In the latter, the vapor is condensed to liquid, and both the condensate and any unevaporated liquid drain into the upper vessel 22. From the latter, the liquid descends by gravity through conduit 24 into the lower vessel 23, from which the liquid overflows through conduit 21 back to the lower end of the cooling coil I8. During this period, only cool gas is flowing through the conduit H to the generator-absorber.

When heat is again applied to the generator during the expulsion or heating period, gas and liquid temporarily continue to-rise through the cooling coil 18 toward the condenser, as previously described. However, hot vapor, expelled from solution in the generator l0, now flows through the conduit I4 which is in thermal exchange relation with the coiled portion 25 of the conduit 24. This causes heating of the liquid descending in conduit 24 from theupper vessel 22 to the lower vessel 23. The vapor which results from the heating of liquid in conduit 24 rises through the column of liquid in this conduit, preventing downward flow therethrough and causing elevation of liquid therein such that the level of liquid in vessel 23 drops below the opening of conduit 21, and thus terminating delivery of liquid to the cooling coil IS. The vapor condenses to liquid in the condenser 20, the liquid filling the upper vessel 22 to the overflow level determined by the opening in the upper end of the conduit 26, through which latter the liquid returns to the lower vessel 23. Thus, during the heating or expulsion period, fluid circulation through the portion of the circuit including the cooling coil I8 is terminated, and a local circulation may occur between the vessels 22 and 23. The drawing shows the approximate relation of the liquid levels during the heating period.

If conduit 24 is of sufficiently small internal diameter, the rising vapor becomes trapped in the liquid and a well-known pumping effect is produced, creating the above described circulation between the vessels 22 and 23. If the conduit I8 is of sufliciently small capacity, the amount of heat removed from the generator upon instigation of the heating period and prior to termination of liquid delivery to conduit I8 is relatively negligible.

Obviously changes in structure may be made without departing from the invention.

What I claim is:

1. In an absorption refrigeration apparatus having intermittent periods of vapor'expulsion, means forming a circuit for fluid including a conduit normally providing a descending passage for liquid of sufliciently small cross-sectional area that liquid and vapor cannot pass each other therein, and means for heating liquid in said conduit during said expulsion periods to generate vapor and thereby cause upward flow of liquid in said conduit.

2. In an absorption refrigeration apparatus having intermittent periods of vapor expulsion, means forming a circuit for fluid including a coni duit normally providing a descending passage for liquid, and means for heating liquid in said conduit during said expulsion periods to cause generation and upward flow of vapor in said passage and thereby prevent downward flow of liquid therein.

3. In an absorpton refrigeration apparatus having intermittent periods of vapor expulsion, means forming a circuit for fluid including a conduit normally providing a descending passage for liquid, means for heating liquid in said conduit during said expulsion periods to cause generation and upward flow of vapor in said passage and thereby prevent downward flow of liquid therein, and means for condensing said vapor.

4. In an intermittent absorption refrigeration apparatus, means forming a circuit for fluid including an upper vessel, a lower vessel, and a conduit connecting said vessels to provide a descending passage for liquid from said upper vessel to said lower vessel during the absorption periods, and means for heating liquid in said conduit during the expulsion periods to cause generation of vapor and thereby prevent downward flow of liquid.

5. In an intermittent absorption refrigeration apparatus, means forming a circuit for fluid including an upper vessel, a lower vessel, and a conduit connecting said vessels to provide a descending passage for liquid from said upper vesflsel to said lower vessel during the absorption periods, means for heating liquid in said conduit during the expulsion periods to cause generation of vapor and thereby prevent downward flow of liquid, and means for condensing said vapor.

6. In an intermittent absorption refrigeration apparatus, means forming a circuit for fluid including an upper vessel, a lower vessel, and a conduit connecting said vessels to provide a descending passage for liquid from said upper vessel to said lower vessel during-the absorption periods, means for heating liquid in said conduit during the expulsion periods to cause generation of vapor and thereby cause upward flow of liquid in said conduit, and an overflow connection from said upper vessel to said lower vessel.

7. In an intermittent absorption refrigeration apparatus, means forming a circuit for fluid including an upper vessel, a lower vessel, and a conduit connecting said vessels to provide a descending passage for liquid from said upper vessel to said lower vessel during the absorption periods, means for heating liquid in said conduit during the expulsion periods to cause generation of vapor and thereby cause upward flow of liquid in said conduit, an overflow connection from said upper vessel to said lower vessel, and means communicating with said upper vessel for condensing said vapor.

8. In an absorption refrigeration apparatus, means forming a circuit for fluid including a conduit normally providing a descending passage for liquid, and means for intermittently heating liquid in said conduit to cause generation and upward flow of vapor in said passage and thereby prevent downward flowof liquid therein.

9. In an absorption refrigeration apparatus, means forming a circuit for fluid including a conduit normally providing a descending passage for liquid, means for intermittently heating liquid in said conduit to cause generation and upward flow of vapor in said passage and thereby prevent downward flow of liquid therein, and means for condensing said vapor.

10. In an absorption refrigeration apparatus, means forming a circuit for fluid including a thermosiphon element normally providing a descending passage for liquid, and means for intermittently heating liquid in said element to cause generation of vapor in said element and thereby prevent downward flow of liquid therein.

11. In an absorption refrigeration apparatus, means forming a circuit for fluid including a thermosiphon element normally providing a descending passage for liquid, means for intermittently heating liquid in said element to cause generation of vapor in said element and thereby prevent downward flow of liquid therein, and means for condensing said vapor.

12. In refrigeration apparatus of the intermittent absorption type including a generator-absorber, an intermittent cooling system for said generator-absorber comprising means forming a closed fluid circuit having an upper condensing portion between opposed thermosiphon elements, one of said elements extending in heat transfer relation with said generator-absorber, and means for heating the other of said thermosiphon elements during the generating period.

13. In refrigeration'apparatus of the intermittent absorption type including a generator-absorber, an intermittent cooling system for said generator-absorber comprising means forming a closed fluid circuit having an upper condensing portion between opposed thermosiphon elements, one of said elements extending in heat transfer relation with said generator-absorber, and means for conducting vapor to and from said generatorabsorber in heat exchange relation with the other of said thermosiphon elements.

14. Inrefrigeration apparatus of the intermittent absorption type including a generator-absorber, an intermittent cooling system for said generator-absorber comprising means forming a I closed fluid circuit having an upper condensing portion between opposed thermosiphon elements,

one of said elements extending in heat transfer relation with said generator-absorber, and means for simultaneously heating said generator-absorber and the other of said thermosiphon elements.

15. In refrigeration apparatus of the intermittent absorption type including a generator-absorber, a cooling element for said generator-absorber comprising a thermosiphon element, a condenser at a level above said generator-absorber and connected to said element, and a descending return conduit from said condenser to said cooling element including a second thermosiphon element forming a closed fluid circuit, and means for simultaneously heatingsaid generatorabsorber and said second thermosiphon element.

a descending return conduit from said receiver to said thermosiphon element including a second thermosiphon element and forming a closed fluid circuit, and a conduit for conducting vapor to and from said generator-absorber extending in heat transfer relation with said second thermosiphon.

17. .An intermittent cooling system comprising means forming a closed fluid circuit including opposed thermosiphon elements and a condenser between the upper ends of said elements, one of said elements being adapted for heat transfer from an object to be cooled, and means for intermittently heating the other of said thermosiphon elements.

CARL GEORG MUNTERS. 

